Aharonov-Casher oscillations of spin current through a multichannel mesoscopic ring

TL;DR

This paper investigates how Rashba spin-orbit interaction and magnetic fields influence Aharonov-Casher oscillations of spin current in a multichannel mesoscopic ring, providing analytical insights into spin conductance behavior.

Contribution

It introduces an analytical model for spin conductance in a multichannel ring considering finite width and external magnetic fields, extending previous single-channel analyses.

Findings

Finite width broadens and damps AC oscillations.

External magnetic field induces new spin conductance components.

Weak magnetic fields can control spin polarization direction.

Abstract

The Aharonov-Casher (AC) oscillations of spin current through a 2D ballistic ring in the presence of Rashba spin-orbit interaction and external magnetic field has been calculated using the semiclassical path integral method. For classically chaotic trajectories the Fokker-Planck equation determining dynamics of the particle spin polarization has been derived. On the basis of this equation an analytic expression for the spin conductance has been obtained taking into account a finite width of the ring arms carrying large number of conducting channels. It was shown that the finite width results in a broadening and damping of spin current AC oscillations. We found that an external magnetic field leads to appearance of new nondiagonal components of the spin conductance, allowing thus by applying a rather weak magnetic field to change a direction of the transmitted spin current polarization.